Tag: ‘Kyoto-University’

Researchers at Kyoto University have developed new semiconductor laser technology that allows the shape of beams to be tailored freely and that can output beams up to 10 times more compact than existing beams – a development that could lead to a tenfold increase in the storage capacity of optical discs. Research results were published in the June 22 edition of British science journal Nature.

The Kyoto University group, led by professor Susumu Noda, worked with Kyoto-based Rohm Co., Ltd. and the Japan Science and Technology Agency (JST) to engineer layers of photonic crystals consisting of tens of thousands of small holes, which were incorporated into 0.5 mm x 0.5 mm semiconductor chips. The photonic crystal layer works as an optical resonator, with each individual hole functioning as a tiny mirror that causes the light to resonate in the semiconductor until it is emitted as laser light. The result is a laser beam with a diameter up to 10 times smaller and with properties different from those of conventional semiconductor lasers.

According to the researchers, these new semiconductor lasers were able to produce a range of beam patterns while maintaining stable single-mode oscillation. The ability to control the oscillation direction of light in this way could lead to the development of compact lasers capable of producing diverse beam patterns on demand, such as hollow beams (with cross-sections that look like donuts), concentric hollow beams (donuts within donuts), and other shapes that have heretofore been impossible to form.

Controlling the oscillation direction of light also means that lasers can be focused into ultra-thin beams, enabling a tenfold increase in the density of data storage on discs without changing the wavelength of the laser. Using blue lasers such as those used in Blu-ray disc technology could lead to DVDs with hundreds of gigabytes of capacity.

Potential applications are not limited to ultra-high density storage media. Ultra-thin, hollow beams could be used as "tweezers" for trapping and moving microscopic particles, which could bring a new level of precision to molecular-level processing and fabrication. Hidemi Takasu, Rohm's research director, says, "In addition to seeing our research applied to next-generation DVD technology, we hope it can be applied to imaging technology that uses lasers to project precise images directly onto the human retina."

On April 7, Robo Garage, a venture company of Kyoto University, unveiled a slender and agile biped female robot.

Named FT (short for "Female Type"), the robot has a plastic and carbon fiber body, weighs 800 grams (1.8 lbs.), and stands 35 centimeters (13 inches) tall. Her 23 joints enable her to perform a range of fashion model type moves, like arching her back and swinging her hips as she walks, as well as runway-style turns. FT's components were designed and arranged to create a feminine body line.

Robo Garage, who spent about one year working to realize its dream of creating a feminine robot, has not yet determined whether FT will be made commercially available.

"In developing FT, we also sought the advice of pro models," says Tomotaka Takahashi, head of Robo Garage. "I hope that by evoking a sense of familiarity and comfort, FT can expand the potential of robots."

Scientists have succeeded in unraveling the mystery -- at the protein structure level -- of the mechanism at work in the glowing tail of the "Genji firefly" (Luciola cruciata Motschulsky), which is considered to have the highest luminous efficiency of any known source of light. The results of the joint research carried by the Institute of Physical and Chemical Research (RIKEN) and Kyoto University are to be published in the March 16 edition of the British science journal Nature.

By tinkering with the chemical composition of luciferase (a bioluminescent enzyme), the research team succeeded in changing the emission color from its normal greenish-yellow to orange and red. Researchers are now attempting to recreate the blue glow of the sea firefly (Vargula hilgendorfii) and firefly squid (Watasenia scintillans) in order to have all three primary colors at their fingertips.

"This might prove useful in applications such as short-term emergency lighting when no source of electricity or combustion is available," says Kyoto University professor Hiroaki Kato. "Light could be created by mixing up a liquid protein solution."

Anytime energy is converted into light, there is some loss due to heat. Luminous efficiency is a measure of the proportion of energy supplied to a light source that is effectively converted into visible light energy (i.e. the amount not lost to heat or infrared radiation). The luminous efficiency of incandescent light bulbs is around 10%, while fluorescent light is around 20% and LED is around 30%. Firefly tails are significantly higher, at 90%. Scientists were aware that the Genji firefly used luciferase in combination with luciferin (a light-emitting substrate) and adenosine triphosphate (ATP) to produce light, but the detailed workings of the mechanism have until now remained a mystery.